Mobile traffic globally is soaring, and its rate of growth is accelerating, spurred by a surge in smartphones and tablets, as well as 4G connections.

The average data use of the growing legions of mobile users is rising steeply as well. The traffic per month of the average mobile user in 2012 was 201MB. That volume included on average one hour of video, two hours of audio, one video call, and one app download.

But in five years, by end of 2017, the average traffic per month will be 2GB: 10 hours of video, 15 hours of audio, five video calls and 15 app downloads, according to data and projections in the annual Cisco Visual Networking Index (VNI) for mobile traffic globally.

Those averages vary widely based on regions. North American mobile users for example averaged 752MB per month in 2012 and are projected to reach 6,171MB per month in 2017. By contrast, Asia Pacific averaged 136MB per month last year and will hit 1,788 in 2017.

According to Cisco, North American mobile users will grow in five years from 288 million to 316 million, a compound annual growth rate (CAGR) of 1.9%. Globally, the number will jump by nearly 1 billion in that span, from 4.3 billion to 5.2 billion.

The growth in the number of devices will be much higher, and at a much faster rate. In North America, all mobile devices (including machine-to-machine units) will rise from 459 million in 2012 to 841 million in 2017, a CAGR of nearly 13%. The growth rate of other regions is lower but their absolute device numbers are, or is expected to be, even higher.

For all of these devices, network speeds are rapidly improving as 4G expands in some markets like the U.S. and 3G networks expand and improve in many other areas. Cisco says average global mobile network speeds will increase seven times, from 0.5Mbps in 2012 to 3.9Mbps in 2017.

One of the more surprising figures is how much of mobile data is already offloaded from cellular networks to alternatives such as Wi-Fi. Worldwide, 33% of mobile traffic was offloaded in 2012. That will increase by half again, to 46% in 2017. In North America, almost half of mobile traffic - 47% - was offloaded last year; by 2017, it could be 66%.

Wi-Fi is a big part of the connectivity picture for mobile users. According to Cisco, average daily Wi-Fi-based data consumption is four times that of cellular. By the end of 2012, the global average daily data consumption per user on cellular was nearly 14MB; on Wi-Fi, the number was just over 55MB.

In 2012, only about 30% of tablet users had cellular connectivity; about 70% relied entirely on Wi-Fi. Those percentages will not change much over the next five years, according to Cisco. In 2017, over 60% of tablets will have only Wi-Fi; and less than 40% will take advantage of cellular.

The spread of 4G, mainly LTE, is having an outsized impact on data traffic. Globally, only about 1% of mobile connections were on 4G networks in 2012. But that accounts for an astounding 14% of global mobile traffic. Cisco projects that 4G will be 10% of all connections in 2013, yet account for 47% of total mobile traffic.

The device population generating this traffic is quickly diversifying. In 2013, for the first time, traffic from smartphones will be greater than traffic from laptops, which have been by far the main driver of mobile data traffic for years.

Smartphones will gain the most share, rising to just over 27% of all mobile-connected devices (including M2M) in 20917. M2M will also expand rapidly to just over 16% of the total. Tablets will be 2.3% and laptops will be 2.6% of the total. Non-smartphones will still account for 50% of all mobile connected devices in 2017.

These different classes of devices will generate different traffic loads. By 2017, Cisco predicts that smartphones will account for just over 67% of all global mobile data traffic. By themselves, smartphones will be responsible for 90 exabytes of data traffic in 2017. By comparison the total mobile traffic from all devices in 2012 was 11 exabytes.

Laptops will have dropped to 14% of the traffic in 2017, from 45% in 2012; tablets will have risen to nearly 12%. Non-smartphones, though the most numerous, will generate just 1.4% of all mobile traffic in five years.

By operating system, Android now has the top spot, surpassing iOS in 2012 in terms of megabytes per month. In September 2012, Android accounted for about 1,300MB per month, iOS for just under 1,000MB per month. They were followed, surprisingly, by PalmOS, then "proprietary" platforms, "Windows" (presumably including Windows Phone as well as Windows-powered laptops), BlackBerry and in distant last place, Linux.

The top apps - the ones generating the most data consumption - for smartphones are: Video and communications, 45% of data consumption; "information" for 12%, web browsing for 6%; social networking, for 7% and music/audio streaming for 4%. Tablets show a similar ranking: video/communictions, 50%; information, 17%; Web browsing 7%; social networking 7%; music/audio, 4%.

Tiered data plans have been a key means by which carriers have and will continue to manage mobile data growth. According to Cisco, by October 2011, tiered plans already accounted for over 65% of all mobile data plans worldwide. But the unlimited plans were consuming much more data on average, 739MB compared to 425MB.

One year later, by September 2012, over 80% of mobile data plans were tiered, consuming on average 922MB compared to 1,261MB on average for unlimited plan users.